The light guide is a device designed to transmit light from a light source to a point at some distance with minimal loss. Light is transmitted through light guide by means of total internal reflection. Generally, the light guide is made of optical grade materials, for example, acrylic resin, polycarbonate, epoxies, and glass. The light guide can be used for transmitting the light of an LED on a PCB to a front panel for use as status indication, can be used for collecting and directing the light to backlight an LCD display or, and can be used as the means for illuminating a pattern on a see through window. Limited by the production cost, a light guide is usually made of optical grade materials, for example, acrylic resin, polycarbonate, epoxies, and glass. The effect of light transmission of the light guide made of the above materials is not ideal. The light guide made of glass is not resistant to vibration and is prone to breakage.